In a storage system, a plurality of storage devices is used to configure a storage array system such as RAID (Redundant Arrays of Inexpensive Disks) in order to enhance fault tolerance and redundancy.
For example, in RAID 5, a plurality of storage devices is used, and an error correction code is distributed and stored in each storage device together with data for data recovery. With this configuration, even if data corruption occurs, data can be restored by using the error correction code. When data access is impossible due to failure of a certain storage device in the RAID system described above, the faulty storage device is replaced by a new storage device to recover the RAID configuration.
When the RAID configuration is rebuilt, data in the new storage device is restored by using the data and error correction code in the storage device other than the new storage device. It is demanded to shorten the time for the recovery as much as possible.